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To validate the integrity of a commercial vehicle's exhaust system's structural design is a challenging job. An integrated approach to use both simulation/modeling and hardware testing must be employed to reduce product development cost. In addition to the considerations of the geometry and configuration specs of 70-90 parts and joints as well as material's thermal and mechanical property data in model development, representative loading must be used. For base excitation type of loading, such as the one experienced by the vehicle's exhaust system, one must decide whether to conduct the time domain transient analysis or frequency domain random vibration analysis. Although both methods are well known, few discussions can be found in the literature regarding their effective use in the framework of product design and development. Based on our study, the random vibration method should be used first for identifying high stress locations in the system and for design optimization.

This paper describes an analytical process for the design of a brake shoe assembly that consists of the linings, shoe table, webs, and rivets. One fundamental performance requirement for the brake shoe assembly is that the linings will not lose clamp force within the desired service life. Key elements of the analytical process involved developing an FEA model with given loading conditions and developing a mathematical model to study the influence parameters of the forces acting on the lining.

Welding has been used extensively in automotive components design due to its flexibility to be applied in manufacturing, high structural strength and low cost. To improve fuel economy and reduce material cost, weight reduction by optimized structural design has been a high priority in auto industry. In the majority of heavy duty vehicle's chassis components design, the ability to predict the mechanical performance of welded joints is the key to success of structural optimization. FEA (finite element analysis) has been used in the industry to analyze welded parts. However, mesh sensitivity and material properties have been major issues due to geometry irregularity, metallurgical degradation of the base material, and inherent residual stress associated with welded joints. An approach, equilibrium-equivalent structural stress method, led by Battelle and through several joint industrial projects (JIP), has been developed.

Virtual proving ground (VPG) simulations have been popular with passenger vehicles. VPG uses LS-DYNA based non-linear contact Finite Element analysis (FEA) to estimate fully analytical road loads and to predict structural components durability with PG road surfaces and tire represented as Finite elements. Heavy vehicle industry has not used these tools extensively in the past due to the complexity of heavy vehicle systems and especially due to the higher number of tires in the vehicle compared to the passenger car. The higher number tires in the heavy vehicle requires more computational analysis duration compared to the passenger car. However due to the recent advancements in computer hardware, virtual proving ground simulations can be used for heavy vehicles. In this study we have used virtual proving ground based simulation studies to predict the durability performance of a trailer suspension frame.

A method for predicting the propensity of a drum brake system to produce noise is presented. The method utilizes finite element models of the individual components of the drum brake system, which have been assembled into the system model of the brake assembly. An important step in this process is the tuning of the dynamic characteristics of the FEA model to ensure validation with experimental tests. Friction is the key element, which defines the behavior of the drum brake system. The system FEA model is assembled by coupling the lining and drum at the contact interface to simulate the friction interaction. This process produces an asymmetric stiffness matrix. A complex eigenvalue analysis identifies the system dynamic characteristics such as the frequency and damping for each vibration mode. The damping values reveal which modes are unstable and therefore likely to produce noise.

Only products with high quality, low cost, and short concept-to-customer time will continue to have a high market share. For this reason, auto parts suppliers must strive to gain superior engineering capability. One key step in this pursuit is to implement widespread CAE (Computer-Aided-Engineering) in PDP (product development process) [1]. FEA (Finite Element Analysis), in particular, has been identified as a subject that deserves concentrated effort. Specifically, FEA needs to be used broadly and effectively in every phase of PDP ranging from concept evaluation and prototyping, to pre-production design and troubleshooting. However, resource requirement and process quality assurance are major issues in this undertaking [2, 3]. As a counter-measurement, developing product specific FEA guidelines has been identified as a priority strategic initiative. The focus of our presentation is on how to develop standard FEA procedures to guide FEA jobs.

This paper presents a methodology for predicting drum brake performance using FEA (finite element analysis) models considering both the mechanical-structural compliance and thermal effects. The methodology for brake torque prediction with FEA models considering the structural flexibility of the brake components alone has been established [1]. The frictional heat generated during braking causes thermoelastic distortion that modifies the contact pressure distribution at the drum-lining interface. In order to capture this thermal effect, a transient thermal analysis is conducted to predict the transient temperature distribution on the brake components. In the thermal analysis, the heat generated at the drum and lining interface is based on the pressure distribution from the compliant mechanical model. Also, the mechanical properties of the brake components as well as the lining friction are dependent on the temperature distribution.

Nowadays, developing web (World Wide Web) engineering is considered to be a top priority task in many companies. A corporate web information center with broad coverage to support a company's worldwide engineering activities can make the product development and customer support more efficient. First, the archived, readily available product information, knowledge database, and user friendly engineering tools can ease up the more ever demanding engineering jobs. Second, the convenient information storage, retrieval systems and hyperlinks on the web should ensure effective communications among engineers, customers, and suppliers. However, without in-depth planning, the full benefits of web engineering cannot be realized. To be effective, other companion engineering programs must also be instated. This paper reviews the experience we have gained in utilizing web engineering for product development and customer support.

Although computer models for vehicle and sub-system performance simulations have been developed and used extensively in the past several decades, there is currently a need to enhance the overall availability of these types of tools. Increasing demands on vehicle performance targets have intensified the need to obtain rapid feedback on the effects of vehicle modifications throughout the entire development cycle. At the same time, evolution of the PC and development of Web-based applications have contributed to the availability, accessibility, and user-friendliness of sophisticated computer analysis. Web engineering is an ideal approach in supporting globalization and is a cost-effective design-analysis integration business strategy. There is little doubt that this new approach will have positive impacts on product cost, quality, and development cycle time. This paper will show how Microsoft Excel and the Web can be powerful and effective tools in the development process.

Effective linear and nonlinear drum brake system FEA (finite element analysis) models have been developed. Such models can help engineers understand many drum brake related issues, such as lining wear and mechanical and thermal instability. The pressure distribution at the drum and lining interface is an important piece of information in drum brake design. Besides the accurate prediction of the shoe factor, the models can be used to guide designs for improving brake efficiency, reducing component weight and enhancing durability. Progress is also being made in developing hybrid models that integrate FEA models with other analysis techniques. This approach offers engineers easy-to-use design tools. The integrated design and analysis approach will help product design and development by reducing cycle time, cost and improving product quality.

Although the methodology of straight bevel gear tooth form generation has been known for quite some time, few references are available in the literature. Presented in this paper are the general numerical procedures of spherical involute and octoid tooth form generations. We have proven that a tooth form generated from the latter approach, by simulating the rotation of a crown gear, matches exactly with the one from the former approach of unwraping a wire from a base circle. The advantage of using general numerical procedures rather than closed form equations is the flexibility of generating both standard and modified gear tooth profiles. In making the forging die, the gear tooth form must be developed with considerations of both the theoretical optimal geometry, and the dimensional compensation for heat treatment distortion.

The effectiveness of computer simulation modeling for product development support is evidenced by its wide-spread usage. For example, finite element analysis (FEA), has been found indispensable for reducing product development cycle time and cost as well as enhancing product quality. Along with other pertinent information, accurately defined loads are necessary for conducting effective FEA for product design optimizations. FEA results using rough estimated loads often do not provide a good basis for design improvement. A better approach is to define loads through system simulation modeling. The development of such a model involves the synthesis of a wide range of product design knowledge along with a systematic process for model correlation. As the technology becomes matured, there is a strong drive to make the process more efficient by integrating the different types of simulation techniques. Two examples are given in this paper.

Contact stress analysis or surface fatigue life prediction is a subject frequently encountered in powertrain component designs. Examples are the design of gears, bearings, cams, and load ramps. In many cases, design evaluations rely on simple analysis, component supplier's suggestions, and prototype testing. One viable technology trend in modern engineering, however, is to use computer simulation and analysis as a design guide. It is universally acknowledged that up-front computer-aided-engineering (CAE) will reduce the product development cycle time and cost, and improve product quality. In addition, this approach provides a good platform for technology growth. Scattered examples on surface durability analytical modeling techniques are available in the literature. But, the most suitable engineering tools for routine product design support are yet to be developed. Currently, a semi-empirical approach is widely used in the industry.